643ac419fa
- Consistently support -q (quiet) and -v (verbose) - Allow specifying numbers with SI prefixes supported by expand_number(3) - Remove 2^31 limit on lines for head(1) MFC after: 2 weeks Reviewed by: lwhsu, pauamma, gbe Relnotes: yes Differential Revision: https://reviews.freebsd.org/D35720
109 lines
3.1 KiB
Groff
109 lines
3.1 KiB
Groff
.\" Copyright (c) 1980, 1990, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)head.1 8.1 (Berkeley) 6/6/93
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.\" $FreeBSD$
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.\"
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.Dd June 12, 2022
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.Dt HEAD 1
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.Os
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.Sh NAME
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.Nm head
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.Nd display first lines of a file
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.Sh SYNOPSIS
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.Nm
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.Op Fl qv
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.Op Fl n Ar count | Fl c Ar bytes
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.Op Ar
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.Sh DESCRIPTION
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This filter displays the first
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.Ar count
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lines or
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.Ar bytes
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of each of the specified files, or of the standard input if no
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files are specified.
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If
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.Ar count
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is omitted it defaults to 10.
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.Pp
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The following options are available:
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.Bl -tag -width indent
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.It Fl c Ar bytes , Fl -bytes Ns = Ns Ar bytes
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Print
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.Ar bytes
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of each of the specified files.
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.It Fl n Ar count , Fl -lines Ns = Ns Ar count
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Print
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.Ar count
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lines of each of the specified files.
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.Pp
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Both
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.Ar count
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and
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.Ar bytes
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may also be specified with size suffixes supported by
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.Xr expand_number 3 .
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.It Fl q , Fl -quiet , Fl -silent
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Suppresses printing of headers when multiple files are being examined.
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.It Fl v , Fl -verbose
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Prepend each file with a header.
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.El
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.Pp
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If more than a single file is specified, or if the
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.Fl v
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option is used, each file is preceded by a
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header consisting of the string
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.Dq ==> XXX <==
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where
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.Dq XXX
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is the name of the file.
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The
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.Fl q
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flag disables the printing of the header in all cases.
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.Sh EXIT STATUS
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.Ex -std
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.Sh EXAMPLES
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To display the first 500 lines of the file
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.Ar foo :
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.Pp
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.Dl $ head -n 500 foo
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.Pp
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.Nm
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can be used in conjunction with
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.Xr tail 1
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in the following way to, for example, display only line 500 from the file
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.Ar foo :
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.Pp
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.Dl $ head -n 500 foo | tail -n 1
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.Sh SEE ALSO
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.Xr tail 1 ,
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.Xr expand_number 3
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.Sh HISTORY
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The
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.Nm
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command appeared in PWB UNIX.
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